1. Field of the Invention
The present invention relates to a method for manufacturing nitride semiconductor laser element, and nitride semiconductor laser element, and more particularly relates to a method for manufacturing nitride semiconductor laser element which allows making in chip form at good reproducibility, and a nitride semiconductor laser element formed by the method.
2. Background Information
A nitride semiconductor is formed by a compound semiconductor of InxAlyGa1-x-yN (0≦x, 0≦y, 0≦x+y≦1), and semiconductor laser elements in which this is used are subject to an increasing variety of requirements, such as use in a next-generation DVD or another such optical disk system that has a large capacity and allows the recording and reproduction of information at high density, or use in personal computers and other such electronic devices. Accordingly, a great deal of research has gone into a way to manufacture semiconductor laser elements from nitride semiconductors efficiently while maintaining stable characteristics.
For example, a method that has been employed to laminate a nitride semiconductor layer on a wafer and then divide the resulting wafer laterally and longitudinally to form individual chips involves first using etching or cleaving to divide the wafer into bar-shaped pieces so as to form resonator faces of a plurality of laser elements, form a dielectric film as needed on the resonator faces, and then divide the bar-shaped wafers in a direction perpendicular to the resonator face by dicing, scribing, or the like (see, for example, Japanese Laid-Open Patent Application 2000-164964). Another method involves performing the dividing for forming the resonator faces and the subsequent dividing in a direction perpendicular to the resonator face in the opposite order (see, for example, Japanese Laid-Open Patent Application 2002-261370). Moreover, using a laser as a method for scribing has been proposed (see, for example, Japanese Laid-Open Patent Application 2003-46177).
However, when a wafer is cut by one of the above methods, for example, a problem is encountered in that chipping occurs around the cuts.
Also, with a method involving scribing with a scriber or a laser, since breakage is accomplished by applying pressure to scratches made in the wafer surface, the break may occur in an unintended direction depending on the crystal system and so forth of the wafer or laminate, resulting in more chip damage.
Furthermore, with these methods, depending on how the dividing is done, there may be some uneven bumpiness, particularly around the edges of a chip, and this can cause problems in subsequent handling.
Also, burrs, shavings, and the like may adhere to the divided portions, which can lower the yield of laser elements and adversely affect the performance of the laser elements themselves.